diff --git a/composer.json b/composer.json
index 3ed1464ae1aff..aa77cf0cc55ba 100644
--- a/composer.json
+++ b/composer.json
@@ -55,6 +55,7 @@
         "symfony/intl": "self.version",
         "symfony/ldap": "self.version",
         "symfony/lock": "self.version",
+        "symfony/messenger": "self.version",
         "symfony/monolog-bridge": "self.version",
         "symfony/options-resolver": "self.version",
         "symfony/process": "self.version",
diff --git a/src/Symfony/Bundle/FrameworkBundle/Command/MessengerConsumeMessagesCommand.php b/src/Symfony/Bundle/FrameworkBundle/Command/MessengerConsumeMessagesCommand.php
new file mode 100644
index 0000000000000..73032c88aff90
--- /dev/null
+++ b/src/Symfony/Bundle/FrameworkBundle/Command/MessengerConsumeMessagesCommand.php
@@ -0,0 +1,87 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Bundle\FrameworkBundle\Command;
+
+use Psr\Container\ContainerInterface;
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Input\InputArgument;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Input\InputOption;
+use Symfony\Component\Console\Output\OutputInterface;
+use Symfony\Component\Messenger\MessageBusInterface;
+use Symfony\Component\Messenger\Transport\Enhancers\MaximumCountReceiver;
+use Symfony\Component\Messenger\Transport\ReceiverInterface;
+use Symfony\Component\Messenger\Worker;
+
+/**
+ * @author Samuel Roze <samuel.roze@gmail.com>
+ */
+class MessengerConsumeMessagesCommand extends Command
+{
+    protected static $defaultName = 'messenger:consume-messages';
+
+    private $bus;
+    private $receiverLocator;
+
+    public function __construct(MessageBusInterface $bus, ContainerInterface $receiverLocator)
+    {
+        parent::__construct();
+
+        $this->bus = $bus;
+        $this->receiverLocator = $receiverLocator;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function configure()
+    {
+        $this
+            ->setDefinition(array(
+                new InputArgument('receiver', InputArgument::REQUIRED, 'Name of the receiver'),
+                new InputOption('limit', 'l', InputOption::VALUE_REQUIRED, 'Limit the number of received messages'),
+            ))
+            ->setDescription('Consumes messages')
+            ->setHelp(<<<'EOF'
+The <info>%command.name%</info> command consumes messages and dispatches them to the message bus.
+
+    <info>php %command.full_name% <receiver-name></info>
+
+Use the --limit option to limit the number of messages received:
+
+    <info>php %command.full_name% <receiver-name> --limit=10</info>
+EOF
+            )
+        ;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function execute(InputInterface $input, OutputInterface $output)
+    {
+        if (!$this->receiverLocator->has($receiverName = $input->getArgument('receiver'))) {
+            throw new \RuntimeException(sprintf('Receiver "%s" does not exist.', $receiverName));
+        }
+
+        if (!($receiver = $this->receiverLocator->get($receiverName)) instanceof ReceiverInterface) {
+            throw new \RuntimeException(sprintf('Receiver "%s" is not a valid message consumer. It must implement the "%s" interface.', $receiverName, ReceiverInterface::class));
+        }
+
+        if ($limit = $input->getOption('limit')) {
+            $receiver = new MaximumCountReceiver($receiver, $limit);
+        }
+
+        $worker = new Worker($receiver, $this->bus);
+        $worker->run();
+    }
+}
diff --git a/src/Symfony/Bundle/FrameworkBundle/Controller/AbstractController.php b/src/Symfony/Bundle/FrameworkBundle/Controller/AbstractController.php
index 2f1b2a9352410..954961119eb66 100644
--- a/src/Symfony/Bundle/FrameworkBundle/Controller/AbstractController.php
+++ b/src/Symfony/Bundle/FrameworkBundle/Controller/AbstractController.php
@@ -18,6 +18,7 @@
 use Symfony\Component\HttpFoundation\RequestStack;
 use Symfony\Component\HttpFoundation\Session\SessionInterface;
 use Symfony\Component\HttpKernel\HttpKernelInterface;
+use Symfony\Component\Messenger\MessageBusInterface;
 use Symfony\Component\Routing\RouterInterface;
 use Symfony\Component\Security\Core\Authentication\Token\Storage\TokenStorageInterface;
 use Symfony\Component\Security\Core\Authorization\AuthorizationCheckerInterface;
@@ -84,6 +85,7 @@ public static function getSubscribedServices()
             'security.token_storage' => '?'.TokenStorageInterface::class,
             'security.csrf.token_manager' => '?'.CsrfTokenManagerInterface::class,
             'parameter_bag' => '?'.ContainerInterface::class,
+            'message_bus' => '?'.MessageBusInterface::class,
         );
     }
 }
diff --git a/src/Symfony/Bundle/FrameworkBundle/Controller/ControllerTrait.php b/src/Symfony/Bundle/FrameworkBundle/Controller/ControllerTrait.php
index 8b639dc54d812..8d0525dd89907 100644
--- a/src/Symfony/Bundle/FrameworkBundle/Controller/ControllerTrait.php
+++ b/src/Symfony/Bundle/FrameworkBundle/Controller/ControllerTrait.php
@@ -382,4 +382,20 @@ protected function isCsrfTokenValid(string $id, ?string $token): bool
 
         return $this->container->get('security.csrf.token_manager')->isTokenValid(new CsrfToken($id, $token));
     }
+
+    /**
+     * Dispatches a message to the bus.
+     *
+     * @param object $message The message to dispatch
+     *
+     * @final
+     */
+    protected function dispatchMessage($message)
+    {
+        if (!$this->container->has('message_bus')) {
+            throw new \LogicException('The message bus is not enabled in your application. Try running "composer require symfony/messenger".');
+        }
+
+        return $this->container->get('message_bus')->dispatch($message);
+    }
 }
diff --git a/src/Symfony/Bundle/FrameworkBundle/DataCollector/MessengerDataCollector.php b/src/Symfony/Bundle/FrameworkBundle/DataCollector/MessengerDataCollector.php
new file mode 100644
index 0000000000000..99a133d8b1179
--- /dev/null
+++ b/src/Symfony/Bundle/FrameworkBundle/DataCollector/MessengerDataCollector.php
@@ -0,0 +1,93 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Bundle\FrameworkBundle\DataCollector;
+
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\HttpKernel\DataCollector\DataCollector;
+use Symfony\Component\Messenger\MiddlewareInterface;
+
+/**
+ * @author Samuel Roze <samuel.roze@gmail.com>
+ */
+class MessengerDataCollector extends DataCollector implements MiddlewareInterface
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function collect(Request $request, Response $response, \Exception $exception = null)
+    {
+        return $this->data;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getName()
+    {
+        return 'messages';
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function reset()
+    {
+        $this->data = array();
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function handle($message, callable $next)
+    {
+        $debugRepresentation = array(
+            'message' => array(
+                'type' => get_class($message),
+            ),
+        );
+
+        $exception = null;
+        try {
+            $result = $next($message);
+
+            if (is_object($result)) {
+                $debugRepresentation['result'] = array(
+                    'type' => get_class($result),
+                );
+            } else {
+                $debugRepresentation['result'] = array(
+                    'type' => gettype($result),
+                    'value' => $result,
+                );
+            }
+        } catch (\Throwable $exception) {
+            $debugRepresentation['exception'] = array(
+                'type' => get_class($exception),
+                'message' => $exception->getMessage(),
+            );
+        }
+
+        $this->data[] = $debugRepresentation;
+
+        if (null !== $exception) {
+            throw $exception;
+        }
+
+        return $result;
+    }
+
+    public function getMessages(): array
+    {
+        return $this->data;
+    }
+}
diff --git a/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php b/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php
index eb3f48350dd41..15df976355909 100644
--- a/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php
+++ b/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php
@@ -22,6 +22,7 @@
 use Symfony\Component\Lock\Lock;
 use Symfony\Component\Lock\Store\SemaphoreStore;
 use Symfony\Component\Security\Csrf\CsrfTokenManagerInterface;
+use Symfony\Component\Messenger\MessageBusInterface;
 use Symfony\Component\Serializer\Serializer;
 use Symfony\Component\Translation\Translator;
 use Symfony\Component\Validator\Validation;
@@ -102,6 +103,7 @@ public function getConfigTreeBuilder()
         $this->addPhpErrorsSection($rootNode);
         $this->addWebLinkSection($rootNode);
         $this->addLockSection($rootNode);
+        $this->addMessengerSection($rootNode);
 
         return $treeBuilder;
     }
@@ -956,4 +958,35 @@ private function addWebLinkSection(ArrayNodeDefinition $rootNode)
             ->end()
         ;
     }
+
+    private function addMessengerSection(ArrayNodeDefinition $rootNode)
+    {
+        $rootNode
+            ->children()
+                ->arrayNode('messenger')
+                    ->info('Messenger configuration')
+                    ->{!class_exists(FullStack::class) && class_exists(MessageBusInterface::class) ? 'canBeDisabled' : 'canBeEnabled'}()
+                    ->children()
+                        ->arrayNode('routing')
+                            ->useAttributeAsKey('message_class')
+                            ->prototype('array')
+                                ->beforeNormalization()
+                                    ->ifString()
+                                    ->then(function ($v) {
+                                        return array('senders' => array($v));
+                                    })
+                                ->end()
+                                ->children()
+                                    ->arrayNode('senders')
+                                        ->requiresAtLeastOneElement()
+                                        ->prototype('scalar')->end()
+                                    ->end()
+                                ->end()
+                            ->end()
+                        ->end()
+                    ->end()
+                ->end()
+            ->end()
+        ;
+    }
 }
diff --git a/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php b/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php
index b36b179775671..842a51744b9e8 100644
--- a/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php
+++ b/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php
@@ -59,6 +59,8 @@
 use Symfony\Component\Lock\LockInterface;
 use Symfony\Component\Lock\Store\StoreFactory;
 use Symfony\Component\Lock\StoreInterface;
+use Symfony\Component\Messenger\Transport\ReceiverInterface;
+use Symfony\Component\Messenger\Transport\SenderInterface;
 use Symfony\Component\PropertyAccess\PropertyAccessor;
 use Symfony\Component\PropertyInfo\PropertyAccessExtractorInterface;
 use Symfony\Component\PropertyInfo\PropertyDescriptionExtractorInterface;
@@ -266,6 +268,12 @@ public function load(array $configs, ContainerBuilder $container)
             $this->registerLockConfiguration($config['lock'], $container, $loader);
         }
 
+        if ($this->isConfigEnabled($container, $config['messenger'])) {
+            $this->registerMessengerConfiguration($config['messenger'], $container, $loader);
+        } else {
+            $container->removeDefinition('console.command.messenger_consume_messages');
+        }
+
         if ($this->isConfigEnabled($container, $config['web_link'])) {
             if (!class_exists(HttpHeaderSerializer::class)) {
                 throw new LogicException('WebLink support cannot be enabled as the WebLink component is not installed.');
@@ -333,6 +341,10 @@ public function load(array $configs, ContainerBuilder $container)
             ->addTag('validator.constraint_validator');
         $container->registerForAutoconfiguration(ObjectInitializerInterface::class)
             ->addTag('validator.initializer');
+        $container->registerForAutoconfiguration(ReceiverInterface::class)
+            ->addTag('messenger.receiver');
+        $container->registerForAutoconfiguration(SenderInterface::class)
+            ->addTag('messenger.sender');
 
         if (!$container->getParameter('kernel.debug')) {
             // remove tagged iterator argument for resource checkers
@@ -1410,6 +1422,26 @@ private function registerLockConfiguration(array $config, ContainerBuilder $cont
         }
     }
 
+    private function registerMessengerConfiguration(array $config, ContainerBuilder $container, XmlFileLoader $loader)
+    {
+        $loader->load('messenger.xml');
+
+        $senderLocatorMapping = array();
+        $messageToSenderIdsMapping = array();
+        foreach ($config['routing'] as $message => $messageConfiguration) {
+            foreach ($messageConfiguration['senders'] as $sender) {
+                if (null !== $sender) {
+                    $senderLocatorMapping[$sender] = new Reference($sender);
+                }
+            }
+
+            $messageToSenderIdsMapping[$message] = $messageConfiguration['senders'];
+        }
+
+        $container->getDefinition('messenger.sender_locator')->replaceArgument(0, $senderLocatorMapping);
+        $container->getDefinition('messenger.asynchronous.routing.sender_locator')->replaceArgument(1, $messageToSenderIdsMapping);
+    }
+
     private function registerCacheConfiguration(array $config, ContainerBuilder $container)
     {
         $version = new Parameter('container.build_id');
diff --git a/src/Symfony/Bundle/FrameworkBundle/FrameworkBundle.php b/src/Symfony/Bundle/FrameworkBundle/FrameworkBundle.php
index 9511c4bc61ce0..6b1de4f03f33e 100644
--- a/src/Symfony/Bundle/FrameworkBundle/FrameworkBundle.php
+++ b/src/Symfony/Bundle/FrameworkBundle/FrameworkBundle.php
@@ -34,6 +34,7 @@
 use Symfony\Component\HttpKernel\DependencyInjection\RegisterControllerArgumentLocatorsPass;
 use Symfony\Component\HttpKernel\DependencyInjection\RemoveEmptyControllerArgumentLocatorsPass;
 use Symfony\Component\HttpKernel\DependencyInjection\ResettableServicePass;
+use Symfony\Component\Messenger\DependencyInjection\MessengerPass;
 use Symfony\Component\PropertyInfo\DependencyInjection\PropertyInfoPass;
 use Symfony\Component\Routing\DependencyInjection\RoutingResolverPass;
 use Symfony\Component\Serializer\DependencyInjection\SerializerPass;
@@ -118,6 +119,7 @@ public function build(ContainerBuilder $container)
         $container->addCompilerPass(new ResettableServicePass());
         $container->addCompilerPass(new TestServiceContainerWeakRefPass(), PassConfig::TYPE_BEFORE_REMOVING, -32);
         $container->addCompilerPass(new TestServiceContainerRealRefPass(), PassConfig::TYPE_AFTER_REMOVING);
+        $this->addCompilerPassIfExists($container, MessengerPass::class);
 
         if ($container->getParameter('kernel.debug')) {
             $container->addCompilerPass(new AddDebugLogProcessorPass(), PassConfig::TYPE_BEFORE_OPTIMIZATION, -32);
diff --git a/src/Symfony/Bundle/FrameworkBundle/Resources/config/console.xml b/src/Symfony/Bundle/FrameworkBundle/Resources/config/console.xml
index 5611fa3ccdba3..9c1ed0e163780 100644
--- a/src/Symfony/Bundle/FrameworkBundle/Resources/config/console.xml
+++ b/src/Symfony/Bundle/FrameworkBundle/Resources/config/console.xml
@@ -69,6 +69,13 @@
             <tag name="console.command" command="debug:event-dispatcher" />
         </service>
 
+        <service id="console.command.messenger_consume_messages" class="Symfony\Bundle\FrameworkBundle\Command\MessengerConsumeMessagesCommand">
+            <argument type="service" id="message_bus" />
+            <argument type="service" id="messenger.receiver_locator" />
+
+            <tag name="console.command" command="messenger:consume-messages" />
+        </service>
+
         <service id="console.command.router_debug" class="Symfony\Bundle\FrameworkBundle\Command\RouterDebugCommand">
             <argument type="service" id="router" />
             <tag name="console.command" command="debug:router" />
diff --git a/src/Symfony/Bundle/FrameworkBundle/Resources/config/messenger.xml b/src/Symfony/Bundle/FrameworkBundle/Resources/config/messenger.xml
new file mode 100644
index 0000000000000..79e9a3980b5e5
--- /dev/null
+++ b/src/Symfony/Bundle/FrameworkBundle/Resources/config/messenger.xml
@@ -0,0 +1,70 @@
+<?xml version="1.0" ?>
+
+<container xmlns="http://symfony.com/schema/dic/services"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://symfony.com/schema/dic/services http://symfony.com/schema/dic/services/services-1.0.xsd">
+
+    <services>
+        <defaults public="false" />
+
+        <!-- Bus -->
+        <service id="message_bus" class="Symfony\Component\Messenger\MessageBus" public="true">
+            <argument type="tagged" tag="message_bus_middleware" /> <!-- Middlewares -->
+        </service>
+
+        <service id="Symfony\Component\Messenger\MessageBusInterface" alias="message_bus" />
+
+        <!-- Handlers -->
+        <service id="messenger.handler_resolver" class="Symfony\Component\Messenger\ContainerHandlerLocator">
+            <argument type="service" id="service_container"/>
+        </service>
+
+        <service id="messenger.middleware.call_message_handler" class="Symfony\Component\Messenger\Middleware\HandleMessageMiddleware">
+            <argument type="service" id="messenger.handler_resolver" />
+
+            <tag name="message_bus_middleware" priority="-10" />
+        </service>
+
+        <!-- Asynchronous -->
+        <service id="messenger.asynchronous.routing.sender_locator" class="Symfony\Component\Messenger\Asynchronous\Routing\SenderLocator">
+            <argument type="service" id="messenger.sender_locator" />
+            <argument /> <!-- Message to sender ID mapping -->
+        </service>
+        <service id="messenger.asynchronous.middleware.send_message_to_producer" class="Symfony\Component\Messenger\Asynchronous\Middleware\SendMessageMiddleware">
+            <argument type="service" id="messenger.asynchronous.routing.sender_locator" />
+
+            <tag name="message_bus_middleware" priority="-5" />
+        </service>
+
+        <!-- Message encoding/decoding -->
+        <service id="messenger.transport.serialize_message_with_type_in_headers" class="Symfony\Component\Messenger\Transport\Serialization\Serializer">
+            <argument type="service" id="serializer" />
+        </service>
+
+        <service id="messenger.transport.default_encoder" alias="messenger.transport.serialize_message_with_type_in_headers" public="true" />
+        <service id="messenger.transport.default_decoder" alias="messenger.transport.serialize_message_with_type_in_headers" public="true" />
+
+        <!-- Logging & Debug -->
+        <service id="messenger.middleware.debug.logging" class="Symfony\Component\Messenger\Debug\LoggingMiddleware">
+            <argument type="service" id="logger" />
+
+            <tag name="message_bus_middleware" priority="10" />
+            <tag name="monolog.logger" channel="messenger" />
+        </service>
+
+        <service id="data_collector.messenger" class="Symfony\Bundle\FrameworkBundle\DataCollector\MessengerDataCollector">
+            <tag name="data_collector" template="@WebProfiler/Collector/messages.html.twig" id="messages" priority="100" />
+            <tag name="message_bus_middleware" />
+        </service>
+
+        <!-- Discovery -->
+        <service id="messenger.receiver_locator">
+            <tag name="container.service_locator" />
+            <argument type="collection" />
+        </service>
+        <service id="messenger.sender_locator">
+            <tag name="container.service_locator" />
+            <argument type="collection" />
+        </service>
+    </services>
+</container>
diff --git a/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/ConfigurationTest.php b/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/ConfigurationTest.php
index 84921d9737d60..9f9e13317d7db 100644
--- a/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/ConfigurationTest.php
+++ b/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/ConfigurationTest.php
@@ -17,6 +17,7 @@
 use Symfony\Component\Config\Definition\Exception\InvalidConfigurationException;
 use Symfony\Component\Config\Definition\Processor;
 use Symfony\Component\Lock\Store\SemaphoreStore;
+use Symfony\Component\Messenger\MessageBusInterface;
 
 class ConfigurationTest extends TestCase
 {
@@ -249,6 +250,10 @@ class_exists(SemaphoreStore::class) && SemaphoreStore::isSupported() ? 'semaphor
                     ),
                 ),
             ),
+            'messenger' => array(
+                'enabled' => !class_exists(FullStack::class) && class_exists(MessageBusInterface::class),
+                'routing' => array(),
+            ),
         );
     }
 }
diff --git a/src/Symfony/Bundle/WebProfilerBundle/Resources/views/Collector/messages.html.twig b/src/Symfony/Bundle/WebProfilerBundle/Resources/views/Collector/messages.html.twig
new file mode 100644
index 0000000000000..f6be519f17372
--- /dev/null
+++ b/src/Symfony/Bundle/WebProfilerBundle/Resources/views/Collector/messages.html.twig
@@ -0,0 +1,60 @@
+{% extends '@WebProfiler/Profiler/layout.html.twig' %}
+
+{% import _self as helper %}
+
+{% block menu %}
+<span class="label">
+    <span class="icon">{{ include('@WebProfiler/Icon/messages.svg') }}</span>
+    <strong>Messages</strong>
+
+    {% if collector.messages|length > 0 %}
+        <span class="count">
+            <span>{{ collector.messages|length }}</span>
+        </span>
+    {% endif %}
+</span>
+{% endblock %}
+
+{% block panel %}
+    <h2>Messages</h2>
+
+    {% if collector.messages is empty %}
+    <p>No messages</p>
+    {% else %}
+    <table>
+        <thead>
+        <tr>
+            <th>Message</th>
+            <th>Result</th>
+        </tr>
+        </thead>
+        <tbody>
+        {% for message in collector.messages %}
+        <tr>
+            <td>{{ message.message.type }}</td>
+            <td>
+                {% if message.result.type is defined %}
+                    {{ message.result.type }}
+                {% endif %}
+
+                {% if message.exception.type is defined %}
+                    {{ message.exception.type }}
+                {% endif %}
+            </td>
+        </tr>
+        {% endfor %}
+        </tbody>
+    </table>
+    {% endif %}
+{% endblock %}
+
+{% block toolbar %}
+    {% set color_code = 'normal' %}
+    {% set message_count = 0 %}
+    {% set icon %}
+        {{ include('@WebProfiler/Icon/messages.svg') }}
+        <span class="sf-toolbar-value">{{ message_count }}</span>
+    {% endset %}
+
+    {{ include('@WebProfiler/Profiler/toolbar_item.html.twig', { link: 'messages', status: color_code }) }}
+{% endblock %}
diff --git a/src/Symfony/Bundle/WebProfilerBundle/Resources/views/Icon/messages.svg b/src/Symfony/Bundle/WebProfilerBundle/Resources/views/Icon/messages.svg
new file mode 100644
index 0000000000000..2fd49b55fe6d5
--- /dev/null
+++ b/src/Symfony/Bundle/WebProfilerBundle/Resources/views/Icon/messages.svg
@@ -0,0 +1,10 @@
+<svg version="1.1" xmlns="http://www.w3.org/2000/svg" x="0px" y="0px" width="24" height="24" viewBox="0 0 24 24" enable-background="new 0 0 24 24" xml:space="preserve">
+    <g id="Page-1" stroke="none" stroke-width="1" fill="none" fill-rule="evenodd">
+        <g id="Symfony-Icon" fill="#AAAAAA" fill-rule="nonzero">
+            <g id="messages" transform="translate(1.000000, 4.000000)">
+                <polygon id="Shape" points="7 2.56157635 15.8538682 2.56157635 15.8538682 10.9293924 17.4441261 10.9293924 18.6475645 13 19.8510029 10.9293924 22 10.9293924 22 0 7 0"></polygon>
+                <path d="M3.18051576,16 L4.53309456,13.7181965 L15,13.7181965 L15,3 L0,3 L0,13.7181965 L1.82793696,13.7181965 L3.18051576,16 Z M2.75071633,6.14009662 L9.11174785,6.14009662 L9.11174785,6.64251208 L2.75071633,6.64251208 L2.75071633,6.14009662 Z M2.75071633,8.27536232 L12.5071633,8.27536232 L12.5071633,8.77777778 L2.75071633,8.77777778 L2.75071633,8.27536232 Z M2.75071633,10.410628 L12.5071633,10.410628 L12.5071633,10.9130435 L2.75071633,10.9130435 L2.75071633,10.410628 Z" id="Shape"></path>
+            </g>
+        </g>
+    </g>
+</svg>
\ No newline at end of file
diff --git a/src/Symfony/Component/Messenger/Asynchronous/Middleware/SendMessageMiddleware.php b/src/Symfony/Component/Messenger/Asynchronous/Middleware/SendMessageMiddleware.php
new file mode 100644
index 0000000000000..469c5672b9672
--- /dev/null
+++ b/src/Symfony/Component/Messenger/Asynchronous/Middleware/SendMessageMiddleware.php
@@ -0,0 +1,55 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger\Asynchronous\Middleware;
+
+use Symfony\Component\Messenger\Asynchronous\Routing\SenderLocatorInterface;
+use Symfony\Component\Messenger\Asynchronous\Transport\ReceivedMessage;
+use Symfony\Component\Messenger\MiddlewareInterface;
+
+/**
+ * @author Samuel Roze <samuel.roze@gmail.com>
+ */
+class SendMessageMiddleware implements MiddlewareInterface
+{
+    private $senderLocator;
+
+    public function __construct(SenderLocatorInterface $senderLocator)
+    {
+        $this->senderLocator = $senderLocator;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function handle($message, callable $next)
+    {
+        if ($message instanceof ReceivedMessage) {
+            return $next($message->getMessage());
+        }
+
+        if (!empty($senders = $this->senderLocator->getSendersForMessage($message))) {
+            foreach ($senders as $sender) {
+                if (null === $sender) {
+                    continue;
+                }
+
+                $sender->send($message);
+            }
+
+            if (!in_array(null, $senders, true)) {
+                return;
+            }
+        }
+
+        return $next($message);
+    }
+}
diff --git a/src/Symfony/Component/Messenger/Asynchronous/Routing/SenderLocator.php b/src/Symfony/Component/Messenger/Asynchronous/Routing/SenderLocator.php
new file mode 100644
index 0000000000000..24a85332250c3
--- /dev/null
+++ b/src/Symfony/Component/Messenger/Asynchronous/Routing/SenderLocator.php
@@ -0,0 +1,44 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger\Asynchronous\Routing;
+
+use Psr\Container\ContainerInterface;
+
+/**
+ * @author Samuel Roze <samuel.roze@gmail.com>
+ */
+class SenderLocator implements SenderLocatorInterface
+{
+    private $senderServiceLocator;
+    private $messageToSenderIdsMapping;
+
+    public function __construct(ContainerInterface $senderServiceLocator, array $messageToSenderIdsMapping)
+    {
+        $this->senderServiceLocator = $senderServiceLocator;
+        $this->messageToSenderIdsMapping = $messageToSenderIdsMapping;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getSendersForMessage($message): array
+    {
+        $senderIds = $this->messageToSenderIdsMapping[get_class($message)] ?? $this->messageToSenderIdsMapping['*'] ?? array();
+
+        $senders = array();
+        foreach ($senderIds as $senderId) {
+            $senders[] = $this->senderServiceLocator->get($senderId);
+        }
+
+        return $senders;
+    }
+}
diff --git a/src/Symfony/Component/Messenger/Asynchronous/Routing/SenderLocatorInterface.php b/src/Symfony/Component/Messenger/Asynchronous/Routing/SenderLocatorInterface.php
new file mode 100644
index 0000000000000..d97508b31a2f1
--- /dev/null
+++ b/src/Symfony/Component/Messenger/Asynchronous/Routing/SenderLocatorInterface.php
@@ -0,0 +1,31 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger\Asynchronous\Routing;
+
+use Symfony\Component\Messenger\Transport\SenderInterface;
+
+/**
+ * @author Samuel Roze <samuel.roze@gmail.com>
+ *
+ * @experimental in 4.1
+ */
+interface SenderLocatorInterface
+{
+    /**
+     * Gets the sender (if applicable) for the given message object.
+     *
+     * @param object $message
+     *
+     * @return SenderInterface[]
+     */
+    public function getSendersForMessage($message): array;
+}
diff --git a/src/Symfony/Component/Messenger/Asynchronous/Transport/ReceivedMessage.php b/src/Symfony/Component/Messenger/Asynchronous/Transport/ReceivedMessage.php
new file mode 100644
index 0000000000000..1b1298da63d32
--- /dev/null
+++ b/src/Symfony/Component/Messenger/Asynchronous/Transport/ReceivedMessage.php
@@ -0,0 +1,37 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger\Asynchronous\Transport;
+
+use Symfony\Component\Messenger\Asynchronous\Middleware\SendMessageMiddleware;
+
+/**
+ * Wraps a received message. This is mainly used by the `SendMessageMiddleware` middleware to identify
+ * a message should not be sent if it was just received.
+ *
+ * @see SendMessageMiddleware
+ *
+ * @author Samuel Roze <samuel.roze@gmail.com>
+ */
+final class ReceivedMessage
+{
+    private $message;
+
+    public function __construct($message)
+    {
+        $this->message = $message;
+    }
+
+    public function getMessage()
+    {
+        return $this->message;
+    }
+}
diff --git a/src/Symfony/Component/Messenger/Asynchronous/Transport/WrapIntoReceivedMessage.php b/src/Symfony/Component/Messenger/Asynchronous/Transport/WrapIntoReceivedMessage.php
new file mode 100644
index 0000000000000..dd17a94b13bea
--- /dev/null
+++ b/src/Symfony/Component/Messenger/Asynchronous/Transport/WrapIntoReceivedMessage.php
@@ -0,0 +1,44 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger\Asynchronous\Transport;
+
+use Symfony\Component\Messenger\Transport\ReceiverInterface;
+
+/**
+ * @author Samuel Roze <samuel.roze@gmail.com>
+ */
+class WrapIntoReceivedMessage implements ReceiverInterface
+{
+    private $decoratedReceiver;
+
+    public function __construct(ReceiverInterface $decoratedConsumer)
+    {
+        $this->decoratedReceiver = $decoratedConsumer;
+    }
+
+    public function receive(): iterable
+    {
+        $iterator = $this->decoratedReceiver->receive();
+
+        foreach ($iterator as $message) {
+            try {
+                yield new ReceivedMessage($message);
+            } catch (\Throwable $e) {
+                if (!$iterator instanceof \Generator) {
+                    throw $e;
+                }
+
+                $iterator->throw($e);
+            }
+        }
+    }
+}
diff --git a/src/Symfony/Component/Messenger/ContainerHandlerLocator.php b/src/Symfony/Component/Messenger/ContainerHandlerLocator.php
new file mode 100644
index 0000000000000..4b80d8ca8a9b2
--- /dev/null
+++ b/src/Symfony/Component/Messenger/ContainerHandlerLocator.php
@@ -0,0 +1,41 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger;
+
+use Psr\Container\ContainerInterface;
+use Symfony\Component\Messenger\Exception\NoHandlerForMessageException;
+
+/**
+ * @author Miha Vrhovnik <miha.vrhovnik@gmail.com>
+ * @author Samuel Roze <samuel.roze@gmail.com>
+ */
+class ContainerHandlerLocator implements HandlerLocatorInterface
+{
+    private $container;
+
+    public function __construct(ContainerInterface $container)
+    {
+        $this->container = $container;
+    }
+
+    public function resolve($message): callable
+    {
+        $messageClass = get_class($message);
+        $handlerKey = 'handler.'.$messageClass;
+
+        if (!$this->container->has($handlerKey)) {
+            throw new NoHandlerForMessageException(sprintf('No handler for message "%s".', $messageClass));
+        }
+
+        return $this->container->get($handlerKey);
+    }
+}
diff --git a/src/Symfony/Component/Messenger/Debug/LoggingMiddleware.php b/src/Symfony/Component/Messenger/Debug/LoggingMiddleware.php
new file mode 100644
index 0000000000000..8aea72b26332e
--- /dev/null
+++ b/src/Symfony/Component/Messenger/Debug/LoggingMiddleware.php
@@ -0,0 +1,58 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger\Debug;
+
+use Symfony\Component\Messenger\MiddlewareInterface;
+use Psr\Log\LoggerInterface;
+
+/**
+ * @author Samuel Roze <samuel.roze@gmail.com>
+ */
+class LoggingMiddleware implements MiddlewareInterface
+{
+    private $logger;
+
+    public function __construct(LoggerInterface $logger)
+    {
+        $this->logger = $logger;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function handle($message, callable $next)
+    {
+        $this->logger->debug('Starting handling message {class}', array(
+            'message' => $message,
+            'class' => get_class($message),
+        ));
+
+        try {
+            $result = $next($message);
+        } catch (\Throwable $e) {
+            $this->logger->warning('An exception occurred while handling message {class}', array(
+                'message' => $message,
+                'exception' => $e,
+                'class' => get_class($message),
+            ));
+
+            throw $e;
+        }
+
+        $this->logger->debug('Finished handling message {class}', array(
+            'message' => $message,
+            'class' => get_class($message),
+        ));
+
+        return $result;
+    }
+}
diff --git a/src/Symfony/Component/Messenger/DependencyInjection/MessengerPass.php b/src/Symfony/Component/Messenger/DependencyInjection/MessengerPass.php
new file mode 100644
index 0000000000000..a0dff8ac9ad83
--- /dev/null
+++ b/src/Symfony/Component/Messenger/DependencyInjection/MessengerPass.php
@@ -0,0 +1,139 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger\DependencyInjection;
+
+use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
+use Symfony\Component\DependencyInjection\Compiler\PriorityTaggedServiceTrait;
+use Symfony\Component\DependencyInjection\Compiler\ServiceLocatorTagPass;
+use Symfony\Component\DependencyInjection\ContainerBuilder;
+use Symfony\Component\DependencyInjection\Definition;
+use Symfony\Component\DependencyInjection\Exception\RuntimeException;
+use Symfony\Component\DependencyInjection\Reference;
+use Symfony\Component\Messenger\Handler\ChainHandler;
+
+/**
+ * @author Samuel Roze <samuel.roze@gmail.com>
+ */
+class MessengerPass implements CompilerPassInterface
+{
+    use PriorityTaggedServiceTrait;
+
+    private $messageBusService;
+    private $messageHandlerResolverService;
+    private $handlerTag;
+
+    public function __construct(string $messageBusService = 'message_bus', string $messageHandlerResolverService = 'messenger.handler_resolver', string $handlerTag = 'message_handler')
+    {
+        $this->messageBusService = $messageBusService;
+        $this->messageHandlerResolverService = $messageHandlerResolverService;
+        $this->handlerTag = $handlerTag;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function process(ContainerBuilder $container)
+    {
+        if (!$container->hasDefinition($this->messageBusService)) {
+            return;
+        }
+
+        if (!$container->getParameter('kernel.debug') || !$container->has('logger')) {
+            $container->removeDefinition('messenger.middleware.debug.logging');
+        }
+
+        $this->registerReceivers($container);
+        $this->registerHandlers($container);
+    }
+
+    private function registerHandlers(ContainerBuilder $container)
+    {
+        $handlersByMessage = array();
+
+        foreach ($container->findTaggedServiceIds($this->handlerTag, true) as $serviceId => $tags) {
+            foreach ($tags as $tag) {
+                $handles = $tag['handles'] ?? $this->guessHandledClass($container, $serviceId);
+
+                if (!class_exists($handles)) {
+                    $messageClassLocation = isset($tag['handles']) ? 'declared in your tag attribute "handles"' : 'declared in `__invoke` function';
+
+                    throw new RuntimeException(sprintf('The message class "%s" %s of service "%s" does not exist.', $messageClassLocation, $handles, $serviceId));
+                }
+
+                $priority = $tag['priority'] ?? 0;
+                $handlersByMessage[$handles][$priority][] = new Reference($serviceId);
+            }
+        }
+
+        foreach ($handlersByMessage as $message => $handlers) {
+            krsort($handlersByMessage[$message]);
+            $handlersByMessage[$message] = call_user_func_array('array_merge', $handlersByMessage[$message]);
+        }
+
+        $definitions = array();
+        foreach ($handlersByMessage as $message => $handlers) {
+            if (1 === count($handlers)) {
+                $handlersByMessage[$message] = current($handlers);
+            } else {
+                $d = new Definition(ChainHandler::class, array($handlers));
+                $d->setPrivate(true);
+                $serviceId = hash('sha1', $message);
+                $definitions[$serviceId] = $d;
+                $handlersByMessage[$message] = new Reference($serviceId);
+            }
+        }
+        $container->addDefinitions($definitions);
+
+        $handlersLocatorMapping = array();
+        foreach ($handlersByMessage as $message => $handler) {
+            $handlersLocatorMapping['handler.'.$message] = $handler;
+        }
+
+        $handlerResolver = $container->getDefinition($this->messageHandlerResolverService);
+        $handlerResolver->replaceArgument(0, ServiceLocatorTagPass::register($container, $handlersLocatorMapping));
+    }
+
+    private function guessHandledClass(ContainerBuilder $container, string $serviceId): string
+    {
+        $reflection = $container->getReflectionClass($container->getDefinition($serviceId)->getClass());
+
+        try {
+            $method = $reflection->getMethod('__invoke');
+        } catch (\ReflectionException $e) {
+            throw new RuntimeException(sprintf('Service "%s" should have an `__invoke` function.', $serviceId));
+        }
+
+        $parameters = $method->getParameters();
+        if (1 !== count($parameters)) {
+            throw new RuntimeException(sprintf('`__invoke` function of service "%s" must have exactly one parameter.', $serviceId));
+        }
+
+        $parameter = $parameters[0];
+        if (null === $parameter->getClass()) {
+            throw new RuntimeException(sprintf('The parameter of `__invoke` function of service "%s" must type hint the message class it handles.', $serviceId));
+        }
+
+        return $parameter->getClass()->getName();
+    }
+
+    private function registerReceivers(ContainerBuilder $container)
+    {
+        $receiverMapping = array();
+        foreach ($container->findTaggedServiceIds('messenger.receiver') as $id => $tags) {
+            foreach ($tags as $tag) {
+                $receiverMapping[$tag['id'] ?? $id] = new Reference($id);
+            }
+        }
+
+        $container->getDefinition('messenger.receiver_locator')->replaceArgument(0, $receiverMapping);
+    }
+}
diff --git a/src/Symfony/Component/Messenger/Exception/ExceptionInterface.php b/src/Symfony/Component/Messenger/Exception/ExceptionInterface.php
new file mode 100644
index 0000000000000..56f665b9ee804
--- /dev/null
+++ b/src/Symfony/Component/Messenger/Exception/ExceptionInterface.php
@@ -0,0 +1,21 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger\Exception;
+
+/**
+ * Base Message component's exception.
+ *
+ * @author Samuel Roze <samuel.roze@gmail.com>
+ */
+interface ExceptionInterface
+{
+}
diff --git a/src/Symfony/Component/Messenger/Exception/NoHandlerForMessageException.php b/src/Symfony/Component/Messenger/Exception/NoHandlerForMessageException.php
new file mode 100644
index 0000000000000..20f6fcd326b50
--- /dev/null
+++ b/src/Symfony/Component/Messenger/Exception/NoHandlerForMessageException.php
@@ -0,0 +1,19 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger\Exception;
+
+/**
+ * @author Samuel Roze <samuel.roze@gmail.com>
+ */
+class NoHandlerForMessageException extends \RuntimeException implements ExceptionInterface
+{
+}
diff --git a/src/Symfony/Component/Messenger/Handler/ChainHandler.php b/src/Symfony/Component/Messenger/Handler/ChainHandler.php
new file mode 100644
index 0000000000000..f73f92838101a
--- /dev/null
+++ b/src/Symfony/Component/Messenger/Handler/ChainHandler.php
@@ -0,0 +1,48 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger\Handler;
+
+/**
+ * Represents a collection of message handlers.
+ *
+ * @author Samuel Roze <samuel.roze@gmail.com>
+ */
+class ChainHandler
+{
+    /**
+     * @var callable[]
+     */
+    private $handlers;
+
+    /**
+     * @param callable[] $handlers
+     */
+    public function __construct(array $handlers)
+    {
+        if (empty($handlers)) {
+            throw new \InvalidArgumentException('A collection of message handlers requires at least one handler.');
+        }
+
+        $this->handlers = $handlers;
+    }
+
+    public function __invoke($message)
+    {
+        $results = array();
+
+        foreach ($this->handlers as $handler) {
+            $results[] = $handler($message);
+        }
+
+        return $results;
+    }
+}
diff --git a/src/Symfony/Component/Messenger/HandlerLocator.php b/src/Symfony/Component/Messenger/HandlerLocator.php
new file mode 100644
index 0000000000000..232c961169e8c
--- /dev/null
+++ b/src/Symfony/Component/Messenger/HandlerLocator.php
@@ -0,0 +1,41 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger;
+
+use Symfony\Component\Messenger\Exception\NoHandlerForMessageException;
+
+/**
+ * @author Samuel Roze <samuel.roze@gmail.com>
+ */
+class HandlerLocator implements HandlerLocatorInterface
+{
+    /**
+     * Maps a message (its class) to a given handler.
+     */
+    private $messageToHandlerMapping;
+
+    public function __construct(array $messageToHandlerMapping = array())
+    {
+        $this->messageToHandlerMapping = $messageToHandlerMapping;
+    }
+
+    public function resolve($message): callable
+    {
+        $messageKey = get_class($message);
+
+        if (!isset($this->messageToHandlerMapping[$messageKey])) {
+            throw new NoHandlerForMessageException(sprintf('No handler for message "%s".', $messageKey));
+        }
+
+        return $this->messageToHandlerMapping[$messageKey];
+    }
+}
diff --git a/src/Symfony/Component/Messenger/HandlerLocatorInterface.php b/src/Symfony/Component/Messenger/HandlerLocatorInterface.php
new file mode 100644
index 0000000000000..089acacc32323
--- /dev/null
+++ b/src/Symfony/Component/Messenger/HandlerLocatorInterface.php
@@ -0,0 +1,33 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger;
+
+use Symfony\Component\Messenger\Exception\NoHandlerForMessageException;
+
+/**
+ * @author Samuel Roze <samuel.roze@gmail.com>
+ *
+ * @experimental in 4.1
+ */
+interface HandlerLocatorInterface
+{
+    /**
+     * Returns the handler for the given message.
+     *
+     * @param object $message
+     *
+     * @throws NoHandlerForMessageException
+     *
+     * @return callable
+     */
+    public function resolve($message): callable;
+}
diff --git a/src/Symfony/Component/Messenger/MessageBus.php b/src/Symfony/Component/Messenger/MessageBus.php
new file mode 100644
index 0000000000000..1843ba02af066
--- /dev/null
+++ b/src/Symfony/Component/Messenger/MessageBus.php
@@ -0,0 +1,59 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger;
+
+/**
+ * @author Samuel Roze <samuel.roze@gmail.com>
+ * @author Matthias Noback <matthiasnoback@gmail.com>
+ */
+class MessageBus implements MessageBusInterface
+{
+    private $middlewares;
+
+    /**
+     * @var MiddlewareInterface[]|null
+     */
+    private $indexedMiddlewares;
+
+    /**
+     * @param MiddlewareInterface[]|iterable $middlewares
+     */
+    public function __construct(iterable $middlewares = array())
+    {
+        $this->middlewares = $middlewares;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function dispatch($message)
+    {
+        return call_user_func($this->callableForNextMiddleware(0), $message);
+    }
+
+    private function callableForNextMiddleware(int $index): callable
+    {
+        if (null === $this->indexedMiddlewares) {
+            $this->indexedMiddlewares = is_array($this->middlewares) ? array_values($this->middlewares) : iterator_to_array($this->middlewares, false);
+        }
+
+        if (!isset($this->indexedMiddlewares[$index])) {
+            return function () {};
+        }
+
+        $middleware = $this->indexedMiddlewares[$index];
+
+        return function ($message) use ($middleware, $index) {
+            return $middleware->handle($message, $this->callableForNextMiddleware($index + 1));
+        };
+    }
+}
diff --git a/src/Symfony/Component/Messenger/MessageBusInterface.php b/src/Symfony/Component/Messenger/MessageBusInterface.php
new file mode 100644
index 0000000000000..1d441ea568ff7
--- /dev/null
+++ b/src/Symfony/Component/Messenger/MessageBusInterface.php
@@ -0,0 +1,31 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger;
+
+/**
+ * @author Samuel Roze <samuel.roze@gmail.com>
+ *
+ * @experimental in 4.1
+ */
+interface MessageBusInterface
+{
+    /**
+     * Dispatches the given message.
+     *
+     * The bus can return a value coming from handlers, but is not required to do so.
+     *
+     * @param object $message
+     *
+     * @return mixed
+     */
+    public function dispatch($message);
+}
diff --git a/src/Symfony/Component/Messenger/Middleware/HandleMessageMiddleware.php b/src/Symfony/Component/Messenger/Middleware/HandleMessageMiddleware.php
new file mode 100644
index 0000000000000..428fd99231bba
--- /dev/null
+++ b/src/Symfony/Component/Messenger/Middleware/HandleMessageMiddleware.php
@@ -0,0 +1,41 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger\Middleware;
+
+use Symfony\Component\Messenger\MiddlewareInterface;
+use Symfony\Component\Messenger\HandlerLocatorInterface;
+
+/**
+ * @author Samuel Roze <samuel.roze@gmail.com>
+ */
+class HandleMessageMiddleware implements MiddlewareInterface
+{
+    private $messageHandlerResolver;
+
+    public function __construct(HandlerLocatorInterface $messageHandlerResolver)
+    {
+        $this->messageHandlerResolver = $messageHandlerResolver;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function handle($message, callable $next)
+    {
+        $handler = $this->messageHandlerResolver->resolve($message);
+        $result = $handler($message);
+
+        $next($message);
+
+        return $result;
+    }
+}
diff --git a/src/Symfony/Component/Messenger/MiddlewareInterface.php b/src/Symfony/Component/Messenger/MiddlewareInterface.php
new file mode 100644
index 0000000000000..98ae70119c488
--- /dev/null
+++ b/src/Symfony/Component/Messenger/MiddlewareInterface.php
@@ -0,0 +1,27 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger;
+
+/**
+ * @author Samuel Roze <samuel.roze@gmail.com>
+ *
+ * @experimental in 4.1
+ */
+interface MiddlewareInterface
+{
+    /**
+     * @param object $message
+     *
+     * @return mixed
+     */
+    public function handle($message, callable $next);
+}
diff --git a/src/Symfony/Component/Messenger/README.md b/src/Symfony/Component/Messenger/README.md
new file mode 100644
index 0000000000000..1b93b36ea0cec
--- /dev/null
+++ b/src/Symfony/Component/Messenger/README.md
@@ -0,0 +1,16 @@
+Messenger Component
+===================
+
+**This Component is experimental**. [Experimental features](https://symfony.com/doc/current/contributing/code/experimental.html)
+are not covered by Symfony's BC-break policy.
+
+The Messenger component helps application send and receive messages to/from other applications or via
+message queues.
+
+Resources
+---------
+
+  * [Contributing](https://symfony.com/doc/current/contributing/index.html)
+  * [Report issues](https://github.com/symfony/symfony/issues) and
+    [send Pull Requests](https://github.com/symfony/symfony/pulls)
+    in the [main Symfony repository](https://github.com/symfony/symfony)
diff --git a/src/Symfony/Component/Messenger/Tests/Asynchronous/Middleware/SendMessageMiddlewareTest.php b/src/Symfony/Component/Messenger/Tests/Asynchronous/Middleware/SendMessageMiddlewareTest.php
new file mode 100644
index 0000000000000..436a6df71a0ed
--- /dev/null
+++ b/src/Symfony/Component/Messenger/Tests/Asynchronous/Middleware/SendMessageMiddlewareTest.php
@@ -0,0 +1,100 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger\Tests\Asynchronous\Middleware;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Messenger\Asynchronous\Middleware\SendMessageMiddleware;
+use Symfony\Component\Messenger\Asynchronous\Routing\SenderLocatorInterface;
+use Symfony\Component\Messenger\Asynchronous\Transport\ReceivedMessage;
+use Symfony\Component\Messenger\Tests\Fixtures\DummyMessage;
+use Symfony\Component\Messenger\Transport\SenderInterface;
+
+class SendMessageMiddlewareTest extends TestCase
+{
+    public function testItSendsTheMessageToAssignedSender()
+    {
+        $message = new DummyMessage('Hey');
+        $sender = $this->createMock(SenderInterface::class);
+        $next = $this->createPartialMock(\stdClass::class, ['__invoke']);
+
+        $middleware = new SendMessageMiddleware(new InMemorySenderLocator(array(
+            $sender,
+        )));
+
+        $sender->expects($this->once())->method('send')->with($message);
+        $next->expects($this->never())->method($this->anything());
+
+        $middleware->handle($message, $next);
+    }
+
+    public function testItAlsoCallsTheNextMiddlewareIfASenderIsNull()
+    {
+        $message = new DummyMessage('Hey');
+        $sender = $this->createMock(SenderInterface::class);
+        $next = $this->createPartialMock(\stdClass::class, ['__invoke']);
+
+        $middleware = new SendMessageMiddleware(new InMemorySenderLocator(array(
+            $sender,
+            null,
+        )));
+
+        $sender->expects($this->once())->method('send')->with($message);
+        $next->expects($this->once())->method($this->anything());
+
+        $middleware->handle($message, $next);
+    }
+
+    public function testItCallsTheNextMiddlewareWhenNoSenderForThisMessage()
+    {
+        $message = new DummyMessage('Hey');
+        $next = $this->createPartialMock(\stdClass::class, ['__invoke']);
+
+        $middleware = new SendMessageMiddleware(new InMemorySenderLocator(array()));
+
+        $next->expects($this->once())->method($this->anything());
+
+        $middleware->handle($message, $next);
+    }
+
+    public function testItSkipsReceivedMessages()
+    {
+        $innerMessage = new DummyMessage('Hey');
+        $message = new ReceivedMessage($innerMessage);
+
+        $sender = $this->createMock(SenderInterface::class);
+        $next = $this->createPartialMock(\stdClass::class, ['__invoke']);
+
+        $middleware = new SendMessageMiddleware(new InMemorySenderLocator(array(
+            $sender,
+        )));
+
+        $sender->expects($this->never())->method('send');
+        $next->expects($this->once())->method('__invoke')->with($innerMessage);
+
+        $middleware->handle($message, $next);
+    }
+}
+
+class InMemorySenderLocator implements SenderLocatorInterface
+{
+    private $senders;
+
+    public function __construct(array $senders)
+    {
+        $this->senders = $senders;
+    }
+
+    public function getSendersForMessage($message): array
+    {
+        return $this->senders;
+    }
+}
diff --git a/src/Symfony/Component/Messenger/Tests/Asynchronous/Routing/SenderLocatorTest.php b/src/Symfony/Component/Messenger/Tests/Asynchronous/Routing/SenderLocatorTest.php
new file mode 100644
index 0000000000000..e92882da39abb
--- /dev/null
+++ b/src/Symfony/Component/Messenger/Tests/Asynchronous/Routing/SenderLocatorTest.php
@@ -0,0 +1,61 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger\Tests\Asynchronous\Routing;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\DependencyInjection\Container;
+use Symfony\Component\Messenger\Asynchronous\Routing\SenderLocator;
+use Symfony\Component\Messenger\Tests\Fixtures\DummyMessage;
+use Symfony\Component\Messenger\Tests\Fixtures\SecondMessage;
+use Symfony\Component\Messenger\Transport\SenderInterface;
+
+class SenderLocatorTest extends TestCase
+{
+    public function testItReturnsTheSenderBasedOnTheMessageClass()
+    {
+        $sender = $this->createMock(SenderInterface::class);
+        $container = new Container();
+        $container->set('my_amqp_sender', $sender);
+
+        $locator = new SenderLocator($container, [
+            DummyMessage::class => [
+                'my_amqp_sender',
+            ]
+        ]);
+
+        $this->assertEquals([$sender], $locator->getSendersForMessage(new DummyMessage('Hello')));
+        $this->assertEquals([], $locator->getSendersForMessage(new SecondMessage()));
+    }
+
+    public function testItSupportsAWildcardInsteadOfTheMessageClass()
+    {
+        $container = new Container();
+
+        $sender = $this->createMock(SenderInterface::class);
+        $container->set('my_amqp_sender', $sender);
+
+        $apiSender = $this->createMock(SenderInterface::class);
+        $container->set('my_api_sender', $apiSender);
+
+        $locator = new SenderLocator($container, [
+            DummyMessage::class => [
+                'my_amqp_sender',
+            ],
+            '*' => [
+                'my_api_sender'
+            ]
+        ]);
+
+        $this->assertEquals([$sender], $locator->getSendersForMessage(new DummyMessage('Hello')));
+        $this->assertEquals([$apiSender], $locator->getSendersForMessage(new SecondMessage()));
+    }
+}
diff --git a/src/Symfony/Component/Messenger/Tests/Fixtures/DummyMessage.php b/src/Symfony/Component/Messenger/Tests/Fixtures/DummyMessage.php
new file mode 100644
index 0000000000000..fb02ca7b866ae
--- /dev/null
+++ b/src/Symfony/Component/Messenger/Tests/Fixtures/DummyMessage.php
@@ -0,0 +1,18 @@
+<?php
+
+namespace Symfony\Component\Messenger\Tests\Fixtures;
+
+class DummyMessage
+{
+    private $message;
+
+    public function __construct(string $message)
+    {
+        $this->message = $message;
+    }
+
+    public function getMessage(): string
+    {
+        return $this->message;
+    }
+}
diff --git a/src/Symfony/Component/Messenger/Tests/Fixtures/SecondMessage.php b/src/Symfony/Component/Messenger/Tests/Fixtures/SecondMessage.php
new file mode 100644
index 0000000000000..98f331cb6dfa4
--- /dev/null
+++ b/src/Symfony/Component/Messenger/Tests/Fixtures/SecondMessage.php
@@ -0,0 +1,7 @@
+<?php
+
+namespace Symfony\Component\Messenger\Tests\Fixtures;
+
+class SecondMessage
+{
+}
diff --git a/src/Symfony/Component/Messenger/Tests/MessageBusTest.php b/src/Symfony/Component/Messenger/Tests/MessageBusTest.php
new file mode 100644
index 0000000000000..86ff30aed089c
--- /dev/null
+++ b/src/Symfony/Component/Messenger/Tests/MessageBusTest.php
@@ -0,0 +1,55 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger\Tests;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Messenger\MessageBus;
+use Symfony\Component\Messenger\MessageBusInterface;
+use Symfony\Component\Messenger\MiddlewareInterface;
+use Symfony\Component\Messenger\Tests\Fixtures\DummyMessage;
+
+class MessageBusTest extends TestCase
+{
+    public function testItHasTheRightInterface()
+    {
+        $bus = new MessageBus();
+
+        $this->assertInstanceOf(MessageBusInterface::class, $bus);
+    }
+
+    public function testItCallsTheMiddlewaresAndChainTheReturnValue()
+    {
+        $message = new DummyMessage('Hello');
+        $responseFromDepthMiddleware = 1234;
+
+        $firstMiddleware = $this->createMock(MiddlewareInterface::class);
+        $firstMiddleware->expects($this->once())
+            ->method('handle')
+            ->with($message, $this->anything())
+            ->will($this->returnCallback(function($message, $next) {
+                return $next($message);
+            }));
+
+        $secondMiddleware = $this->createMock(MiddlewareInterface::class);
+        $secondMiddleware->expects($this->once())
+            ->method('handle')
+            ->with($message, $this->anything())
+            ->willReturn($responseFromDepthMiddleware);
+
+        $bus = new MessageBus([
+            $firstMiddleware,
+            $secondMiddleware,
+        ]);
+
+        $this->assertEquals($responseFromDepthMiddleware, $bus->dispatch($message));
+    }
+}
diff --git a/src/Symfony/Component/Messenger/Tests/Middleware/HandleMessageMiddlewareTest.php b/src/Symfony/Component/Messenger/Tests/Middleware/HandleMessageMiddlewareTest.php
new file mode 100644
index 0000000000000..4098d8526b273
--- /dev/null
+++ b/src/Symfony/Component/Messenger/Tests/Middleware/HandleMessageMiddlewareTest.php
@@ -0,0 +1,39 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger\Tests\Middleware;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Messenger\HandlerLocator;
+use Symfony\Component\Messenger\Middleware\HandleMessageMiddleware;
+use Symfony\Component\Messenger\Tests\Fixtures\DummyMessage;
+
+class HandleMessageMiddlewareTest extends TestCase
+{
+    public function testItCallsTheHandlerAndNextMiddleware()
+    {
+        $message = new DummyMessage('Hey');
+
+        $handler = $this->createPartialMock(\stdClass::class, ['__invoke']);
+        $handler->method('__invoke')->willReturn('Hello');
+
+        $next = $this->createPartialMock(\stdClass::class, ['__invoke']);
+
+        $middleware = new HandleMessageMiddleware(new HandlerLocator(array(
+            DummyMessage::class => $handler,
+        )));
+
+        $handler->expects($this->once())->method('__invoke')->with($message);
+        $next->expects($this->once())->method('__invoke')->with($message);
+
+        $middleware->handle($message, $next);
+    }
+}
diff --git a/src/Symfony/Component/Messenger/Tests/Transport/Serialization/SerializerTest.php b/src/Symfony/Component/Messenger/Tests/Transport/Serialization/SerializerTest.php
new file mode 100644
index 0000000000000..8b6199144b7c7
--- /dev/null
+++ b/src/Symfony/Component/Messenger/Tests/Transport/Serialization/SerializerTest.php
@@ -0,0 +1,47 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger\Tests\Transport\Serialization;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Messenger\Tests\Fixtures\DummyMessage;
+use Symfony\Component\Messenger\Transport\Serialization\Serializer;
+use Symfony\Component\Serializer as SerializerComponent;
+use Symfony\Component\Serializer\Encoder\JsonEncoder;
+use Symfony\Component\Serializer\Normalizer\ObjectNormalizer;
+
+class SerializerTest extends TestCase
+{
+    public function testEncodedIsDecodable()
+    {
+        $serializer = new Serializer(
+            new SerializerComponent\Serializer(array(new ObjectNormalizer()), array('json' => new JsonEncoder()))
+        );
+
+        $message = new DummyMessage('Hello');
+
+        $this->assertEquals($message, $serializer->decode($serializer->encode($message)));
+    }
+
+    public function testEncodedIsHavingTheBodyAndTypeHeader()
+    {
+        $serializer = new Serializer(
+            new SerializerComponent\Serializer(array(new ObjectNormalizer()), array('json' => new JsonEncoder()))
+        );
+
+        $encoded = $serializer->encode(new DummyMessage('Hello'));
+
+        $this->assertArrayHasKey('body', $encoded);
+        $this->assertArrayHasKey('headers', $encoded);
+        $this->assertArrayHasKey('type', $encoded['headers']);
+        $this->assertEquals(DummyMessage::class, $encoded['headers']['type']);
+    }
+}
diff --git a/src/Symfony/Component/Messenger/Tests/WorkerTest.php b/src/Symfony/Component/Messenger/Tests/WorkerTest.php
new file mode 100644
index 0000000000000..0b0411e412f8e
--- /dev/null
+++ b/src/Symfony/Component/Messenger/Tests/WorkerTest.php
@@ -0,0 +1,90 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger\Tests;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Messenger\Asynchronous\Transport\ReceivedMessage;
+use Symfony\Component\Messenger\MessageBusInterface;
+use Symfony\Component\Messenger\Tests\Fixtures\DummyMessage;
+use Symfony\Component\Messenger\Transport\ReceiverInterface;
+use Symfony\Component\Messenger\Worker;
+
+class WorkerTest extends TestCase
+{
+    public function testWorkerDispatchTheReceivedMessage()
+    {
+        $receiver = new CallbackReceiver(function() {
+            yield new DummyMessage('API');
+            yield new DummyMessage('IPA');
+        });
+
+        $bus = $this->createMock(MessageBusInterface::class);
+
+        $bus->expects($this->at(0))->method('dispatch')->with(new ReceivedMessage(new DummyMessage('API')));
+        $bus->expects($this->at(1))->method('dispatch')->with(new ReceivedMessage(new DummyMessage('IPA')));
+
+        $worker = new Worker($receiver, $bus);
+        $worker->run();
+    }
+
+    public function testWorkerDoesNotWrapMessagesAlreadyWrappedInReceivedMessages()
+    {
+        $receiver = new CallbackReceiver(function() {
+            yield new ReceivedMessage(new DummyMessage('API'));
+        });
+
+        $bus = $this->createMock(MessageBusInterface::class);
+
+        $bus->expects($this->at(0))->method('dispatch')->with(new ReceivedMessage(new DummyMessage('API')));
+
+        $worker = new Worker($receiver, $bus);
+        $worker->run();
+    }
+
+    public function testWorkerIsThrowingExceptionsBackToGenerators()
+    {
+        $receiver = new CallbackReceiver(function() {
+            try {
+                yield new DummyMessage('Hello');
+
+                $this->assertTrue(false, 'This should not be called because the exception is sent back to the generator.');
+            } catch (\InvalidArgumentException $e) {
+                // This should be called because of the exception sent back to the generator.
+                $this->assertTrue(true);
+            }
+        });
+
+        $bus = $this->createMock(MessageBusInterface::class);
+
+        $bus->method('dispatch')->willThrowException(new \InvalidArgumentException('Why not'));
+
+        $worker = new Worker($receiver, $bus);
+        $worker->run();
+    }
+}
+
+class CallbackReceiver implements ReceiverInterface
+{
+    private $callable;
+
+    public function __construct(callable $callable)
+    {
+        $this->callable = $callable;
+    }
+
+    public function receive(): iterable
+    {
+        $callable = $this->callable;
+
+        return $callable();
+    }
+}
diff --git a/src/Symfony/Component/Messenger/Transport/Enhancers/MaximumCountReceiver.php b/src/Symfony/Component/Messenger/Transport/Enhancers/MaximumCountReceiver.php
new file mode 100644
index 0000000000000..489d52cd5482a
--- /dev/null
+++ b/src/Symfony/Component/Messenger/Transport/Enhancers/MaximumCountReceiver.php
@@ -0,0 +1,51 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger\Transport\Enhancers;
+
+use Symfony\Component\Messenger\Transport\ReceiverInterface;
+
+/**
+ * @author Samuel Roze <samuel.roze@gmail.com>
+ */
+class MaximumCountReceiver implements ReceiverInterface
+{
+    private $decoratedReceiver;
+    private $maximumNumberOfMessages;
+
+    public function __construct(ReceiverInterface $decoratedReceiver, int $maximumNumberOfMessages)
+    {
+        $this->decoratedReceiver = $decoratedReceiver;
+        $this->maximumNumberOfMessages = $maximumNumberOfMessages;
+    }
+
+    public function receive(): iterable
+    {
+        $iterator = $this->decoratedReceiver->receive();
+        $receivedMessages = 0;
+
+        foreach ($iterator as $message) {
+            try {
+                yield $message;
+            } catch (\Throwable $e) {
+                if (!$iterator instanceof \Generator) {
+                    throw $e;
+                }
+
+                $iterator->throw($e);
+            }
+
+            if (++$receivedMessages >= $this->maximumNumberOfMessages) {
+                break;
+            }
+        }
+    }
+}
diff --git a/src/Symfony/Component/Messenger/Transport/ReceiverInterface.php b/src/Symfony/Component/Messenger/Transport/ReceiverInterface.php
new file mode 100644
index 0000000000000..d7fa8673eabda
--- /dev/null
+++ b/src/Symfony/Component/Messenger/Transport/ReceiverInterface.php
@@ -0,0 +1,22 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger\Transport;
+
+/**
+ * @author Samuel Roze <samuel.roze@gmail.com>
+ *
+ * @experimental in 4.1
+ */
+interface ReceiverInterface
+{
+    public function receive(): iterable;
+}
diff --git a/src/Symfony/Component/Messenger/Transport/SenderInterface.php b/src/Symfony/Component/Messenger/Transport/SenderInterface.php
new file mode 100644
index 0000000000000..a142e1f00995e
--- /dev/null
+++ b/src/Symfony/Component/Messenger/Transport/SenderInterface.php
@@ -0,0 +1,27 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger\Transport;
+
+/**
+ * @author Samuel Roze <samuel.roze@gmail.com>
+ *
+ * @experimental in 4.1
+ */
+interface SenderInterface
+{
+    /**
+     * Sends the given message.
+     *
+     * @param object $message
+     */
+    public function send($message);
+}
diff --git a/src/Symfony/Component/Messenger/Transport/Serialization/DecoderInterface.php b/src/Symfony/Component/Messenger/Transport/Serialization/DecoderInterface.php
new file mode 100644
index 0000000000000..0099356aa3582
--- /dev/null
+++ b/src/Symfony/Component/Messenger/Transport/Serialization/DecoderInterface.php
@@ -0,0 +1,34 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger\Transport\Serialization;
+
+/**
+ * @author Samuel Roze <samuel.roze@gmail.com>
+ *
+ * @experimental in 4.1
+ */
+interface DecoderInterface
+{
+    /**
+     * Decodes the message from an encoded-form.
+     *
+     * The `$encodedMessage` parameter is a key-value array that
+     * describes the message, that will be used by the different adapters.
+     *
+     * The most common keys are:
+     * - `body` (string) - the message body
+     * - `headers` (string<string>) - a key/value pair of headers
+     *
+     * @return object
+     */
+    public function decode(array $encodedMessage);
+}
diff --git a/src/Symfony/Component/Messenger/Transport/Serialization/EncoderInterface.php b/src/Symfony/Component/Messenger/Transport/Serialization/EncoderInterface.php
new file mode 100644
index 0000000000000..cdc4a75e93826
--- /dev/null
+++ b/src/Symfony/Component/Messenger/Transport/Serialization/EncoderInterface.php
@@ -0,0 +1,32 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger\Transport\Serialization;
+
+/**
+ * @author Samuel Roze <samuel.roze@gmail.com>
+ *
+ * @experimental in 4.1
+ */
+interface EncoderInterface
+{
+    /**
+     * Encodes a message to a common format understandable by adapters. The encoded array should only
+     * contain scalar and arrays.
+     *
+     * The most common keys of the encoded array are:
+     * - `body` (string) - the message body
+     * - `headers` (string<string>) - a key/value pair of headers
+     *
+     * @param object $message The object that is put on the MessageBus by the user
+     */
+    public function encode($message): array;
+}
diff --git a/src/Symfony/Component/Messenger/Transport/Serialization/Serializer.php b/src/Symfony/Component/Messenger/Transport/Serialization/Serializer.php
new file mode 100644
index 0000000000000..76d747ad99552
--- /dev/null
+++ b/src/Symfony/Component/Messenger/Transport/Serialization/Serializer.php
@@ -0,0 +1,54 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger\Transport\Serialization;
+
+use Symfony\Component\Serializer\SerializerInterface;
+
+/**
+ * @author Samuel Roze <samuel.roze@gmail.com>
+ */
+class Serializer implements DecoderInterface, EncoderInterface
+{
+    private $serializer;
+    private $format;
+
+    public function __construct(SerializerInterface $serializer, string $format = 'json')
+    {
+        $this->serializer = $serializer;
+        $this->format = $format;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function decode(array $encodedMessage)
+    {
+        if (empty($encodedMessage['body']) || empty($encodedMessage['headers'])) {
+            throw new \InvalidArgumentException('Encoded message should have at least a `body` and some `headers`.');
+        } elseif (empty($encodedMessage['headers']['type'])) {
+            throw new \InvalidArgumentException('Encoded message does not have a `type` header.');
+        }
+
+        return $this->serializer->deserialize($encodedMessage['body'], $encodedMessage['headers']['type'], $this->format);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function encode($message): array
+    {
+        return array(
+            'body' => $this->serializer->serialize($message, $this->format),
+            'headers' => array('type' => get_class($message)),
+        );
+    }
+}
diff --git a/src/Symfony/Component/Messenger/Worker.php b/src/Symfony/Component/Messenger/Worker.php
new file mode 100644
index 0000000000000..25c2897fe60c3
--- /dev/null
+++ b/src/Symfony/Component/Messenger/Worker.php
@@ -0,0 +1,56 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Messenger;
+
+use Symfony\Component\Messenger\Asynchronous\Transport\ReceivedMessage;
+use Symfony\Component\Messenger\Transport\ReceiverInterface;
+
+/**
+ * @author Samuel Roze <samuel.roze@gmail.com>
+ *
+ * @experimental in 4.1
+ */
+class Worker
+{
+    private $receiver;
+    private $bus;
+
+    public function __construct(ReceiverInterface $receiver, MessageBusInterface $bus)
+    {
+        $this->receiver = $receiver;
+        $this->bus = $bus;
+    }
+
+    /**
+     * Receive the messages and dispatch them to the bus.
+     */
+    public function run()
+    {
+        $iterator = $this->receiver->receive();
+
+        foreach ($iterator as $message) {
+            if (!$message instanceof ReceivedMessage) {
+                $message = new ReceivedMessage($message);
+            }
+
+            try {
+                $this->bus->dispatch($message);
+            } catch (\Throwable $e) {
+                if (!$iterator instanceof \Generator) {
+                    throw $e;
+                }
+
+                $iterator->throw($e);
+            }
+        }
+    }
+}
diff --git a/src/Symfony/Component/Messenger/composer.json b/src/Symfony/Component/Messenger/composer.json
new file mode 100644
index 0000000000000..7f7d982dc255f
--- /dev/null
+++ b/src/Symfony/Component/Messenger/composer.json
@@ -0,0 +1,41 @@
+{
+    "name": "symfony/messenger",
+    "type": "library",
+    "description": "Symfony Messenger Component",
+    "keywords": [],
+    "homepage": "https://symfony.com",
+    "license": "MIT",
+    "authors": [
+        {
+            "name": "Samuel Roze",
+            "email": "samuel.roze@gmail.com"
+        },
+        {
+            "name": "Symfony Community",
+            "homepage": "https://symfony.com/contributors"
+        }
+    ],
+    "require": {
+        "php": "^7.1.3"
+    },
+    "require-dev": {
+        "symfony/serializer": "~3.4|~4.0",
+        "symfony/dependency-injection": "~3.4|~4.0",
+        "symfony/property-access": "~3.4|~4.0"
+    },
+    "suggest": {
+        "sroze/enqueue-bridge": "For using the php-enqueue library as an adapter."
+    },
+    "autoload": {
+        "psr-4": { "Symfony\\Component\\Messenger\\": "" },
+        "exclude-from-classmap": [
+            "/Tests/"
+        ]
+    },
+    "minimum-stability": "dev",
+    "extra": {
+        "branch-alias": {
+            "dev-master": "4.0-dev"
+        }
+    }
+}
diff --git a/src/Symfony/Component/Messenger/phpunit.xml.dist b/src/Symfony/Component/Messenger/phpunit.xml.dist
new file mode 100644
index 0000000000000..3eff653caf38c
--- /dev/null
+++ b/src/Symfony/Component/Messenger/phpunit.xml.dist
@@ -0,0 +1,30 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="http://schema.phpunit.de/4.1/phpunit.xsd"
+         backupGlobals="false"
+         colors="true"
+         bootstrap="vendor/autoload.php"
+         failOnRisky="true"
+         failOnWarning="true"
+>
+    <php>
+        <ini name="error_reporting" value="-1" />
+    </php>
+
+    <testsuites>
+        <testsuite name="Symfony Messenger Component Test Suite">
+            <directory>./Tests/</directory>
+        </testsuite>
+    </testsuites>
+
+    <filter>
+        <whitelist>
+            <directory>./</directory>
+            <exclude>
+                <directory>./Tests</directory>
+                <directory>./vendor</directory>
+            </exclude>
+        </whitelist>
+    </filter>
+</phpunit>